I am working on dehydration unit with mole sieve, we are face a moisture breakthrough problem in the mole sieve in the hot season.

The unit contain three bed (A, B,C) two working and one is in regeneration phases, desiccant was changed for the latest 3 years by like to like dessicant. the cycle is 24 hours adsorption, 6h regeneration 5.5h cooldown and 0.5h stand by

Outlet specification is 0.1ppm v recently the performance of the first bed (A) was decreased and the water content reach 0.6 ppm we intends to change the time cycle to 22h adsoption, 5 h regen 6h cool and 0 standby.

Please advice us regarding this problem? what are the possible causes of moistre breakthrough and according to your experience what is the best recommandation or action to avoid this problem?

It's not uncommon to find similar experiences. Has this desiccant been in service for 3 years? Changing the cooling time is unlikely to help. The problem occurs in hot weather probably because the feed gas is warmer and thus contains more moisture. Many units are undersized by vendors to be more competitive. You should also contact the desiccant supplier for help.

Thank you Mr.Bobby for your reply, yes the desiccant is in service for about 3 years, supplier recommend that to check if there is a leakage from the regeneration valves in the second to reduce the cycle time.

Following the adsorption time of the first bed, it was shown that after 22 hours the bed is saturated and the moisture amount increase, so based on this we intends to change the cycle time.